Electrode steam boiler



Aug. 28, 1923. 1,466,013

J. BUCHLI ELECTRODE STEAM BOILER Filed June 2, 1921 ill Patented Aug. 28, 1923..

UNITED STATES JACOB BUCHLI, 0F BADEN, SWITZERLAND, -ASSIGNOR T0 AKTIETNGESELLSCHAFT BRQWN, BOVERI & GIE, OF BADEN, SWITZERLAND.

ELECTRODE STEAM BOILER.

Application filed June 2,

To all whom it may concern:

Be it known that I, JAooB BUoHLI, a citizen of the Swiss Republic, residing at" No. 2 Felsenstrasse, Baden, Switzerland, have invented certain new and useful Improvements in Electrode Steam Boilers, of which the following is a specification.

in electrode steam boilers with electric heating, the output of the boiler is limited by the current density at the electrodes. The surface area of the electrode is considerably diminished by bubbles of steam that form on the electrodes so that the current density is very great at certain points. Sparking occurs; the electrode becomes very hot; current and output become quite irregu lar and uncontrollable, and the sparkinggives rise to decomposition of the water. in order to prevent this, according to this invention, a current of water is passed for each'electrode whereby the latter is constantly washed so that on the onehand its own temperature cannot rise very much higher than that of the boiler water, and on the other hand any bubbles of steam that are formed will be carried away by the stream of water.

Figure 1 represents diagrammatically a simple case of an electrode steam boiler according to the invention.

Figure 2 represents diagrammatically a modification of Figure 1 with a pump for circulating the boiler water and an insulating tube surrounding the electrode.

The essential nature of this invention is illustrated in Fig. 1 of the accompanying drawings, wherein a is the steam boiler, b is the electrode. 9 represents diagrammatically a source of electrical power whose poles are connected to the boiler shell and the electrode respectively. Just underneath the electrode there opens a pipe f through which a strongstream of Water, entering from outside, is directed against the electrode b. In the case of high voltage it is not possible to use an uncovered electrode. Consequently, as shown in Fig. 2, the electrode 1s surrounded by an insulating tube a which opens justbelow the surface of the water and serves also as a guide for the cooling water-issuing from the pipe 7. The cooling water is shown, but only by way of example, as being drawn from the boiler water at e, and returned to the boiler through the pipe f by means of the circulating pump d,

1921. semi no. 474,326.

so that there is a continuous circulation of boiler water through the tube 0. By this means the electrode is cooled and bubbles of steam forming on it are carried away. Further, the entire contents of the boiler are heated uniformly and the insulating tube is less subject to local electrolytic corrosion. The direction of the stream of water follows that of the natural circulation of the water in the boiler, the electrode 5 being washed, by it from the upward direction. The supply pipe f should be narrower at least at its mouth than the insulating pipe 0.

The supply pipe for the cooling water may also be utilized in a peculiar manner for regulating the tube of the steam boiler, without thereby interfering with the washing of the fixed electrode. This is eii'ected as follows:

Above the portion of the pipe ,2'' that is situated inside the boiler, there is arranged a short piece of conducting tube which can be slipped from the outside on to or into the pipe f, and which will form either an intermediate electrode, or is connected to the other pole of the electric supply circuit, or. in the case of polyphase supply cir-- cuits is connected to the zero point. Then, by sliding from the outside, this piece, of tube towards or away from the fixed electrode, the generation of steam can be regulated. According as this piece of tube projects beyond the fixed pipe ,1, it will constitute more or less an extension of the guidance for the cooling water. Instead of driving the stream of water against the electrode-through a separate pipe, as shown in the figures, the stream of water may be passed through the actual tubular electrode which is to be cooled,in which case then a part of the water-guiding pipe must be made of insulating material.

What I claim is 1. An electrically heated steam generator including a boiler shell, an electrode projecting into the boiler water, a pipe projecting through the boiler hell and adapted to deliver a stream of water OVer'the electrode in a direction substantially coincident with the direction of flow of the Water due to convection for the purpose of cooling the electrode and carrying 011' the steam bubbles which are given off by the electrode during operation.

2. An electrically heated steam generator as claimed in claim 1, including a pum 10- as claimed in claim 1, including a tube of lo cated outside the boiler adapted to de iver insulatin material surrounding the elecwater to the delivery pipe, trode an above th outlet of the Water de- 3. An electrically heated steam generator livery pipe, said insulating tube being 5 as claimed in claim 1, including a conneclarger in diameter than the upper orifice of tion between the end of the said pipe remote the water delivery pipe. 5 from the electrode and the Water 1n the upper In testimony whereof I have signed my part of the boiler Water space. name to this specification.

4. An electrically heated steam generator J. BUCHLI. 

